1. Field of the Invention
The present invention relates to a positioning device for aligning first and second mold segments as the mold segments move from an opened position to a closed position.
2. Description of the Related Art
In a typical molding process, e.g., a mold cavity and core, are closed together to define a cavity therebetween and material is injected into the cavity to form a part. During the molding process, the mold cavity and core are repeatedly opened and closed to form multiple parts. Molding processes are used in many industries. In several of these industries, the products being formed must meet rigorous standards and specifications. Hence, the tolerance for misalignment between the first and second segments during the molding process is generally small.
In addition to the mold cavity and core, the mold can also include an intermediate segment that moves relative to the mold cavity and core when the mold is opened and closed. This intermediate segment is configured to engage the part to strip the part from the cavity. In industry, the intermediate segment can be referred to as a stripper plate or a floating plate.
Positioning devices are used to reduce tolerances between the mold cavity and core to form products that meet the appropriate standards and specifications for each industry. The positioning device can include a first member attached to the mold cavity and a second member attached to the mold core. The mold cavity and core are typically spaced from each other when the molds are open and come together to engage each other and align the mold cavity and core as the mold cavity and core close together. Specifically, one of the first and second members can be a male member and the other of the first and second members can be a female member that receives the male member. In a design where the mold includes the intermediate segment, the positioning device can include a third member disposed between the first and second members for engaging the first and second members as the first segment, second segment, and intermediate segment of the mold close together.
The fit between the male member and female member determines the magnitude of potential misalignment between the mold segments. The male and female members typically include bearing surfaces that slide against each other as the first, second, and third members come together as the mold cavity and core close. As a result, these bearing surfaces are susceptible to wear. For example, the mold is typically arranged horizontally such that the segments move relative to each other along a horizontal axis as the mold is opened and closed. Over repeated cycles, gravity can misalign the members of the positioning device thereby increasing the wear of these members. Consequently, as demand for higher productivity increases, the speed of the molding process increases thereby increasing the wear along the bearing surfaces of the positioning device.
Traditionally, when the bearing surfaces became worn, the positioning devices must be replaced in order to maintain proper tolerances. This results in increased cost and unacceptable delays in production. There remains opportunity to improve the positioning device in order to properly align the segments of the mold while also extending the life of the positioning device.